Mr Kenny said he was unaware of whether the letter existed but said he would have it checked immediately and respond to Mr Martin.

In July, Mr Wallace called for an independent investigation into the operation of Nama and said he had “no problem” speaking to gardaí about his allegations that an official sought a payment of €30,000.

A Garda investigation was opened into the allegation made by Mr Wallace in the Dáil.

Mr Wallace raised 24 separate questions about the operations of Nama during two contributions to the Dáil, most focusing on the events surrounding Project Eagle, the sale of a 850-property portfolio in Northern Ireland for about €1.5bn (£1.2 bn).

Mr Kenny was also asked by Sinn Féin President Gerry Adams about safety of ambulances after two wheels came off of an ambulance which was transporting a patient.

Mr Adams called into question the safety of Mercedes Benz ambulances and sought assurances the fleet of ambulances are safe.

In reply, Mr Kenny said he was aware of the incident and cited an incident when the wheel of his own car was dislodged.

He said that the wheel nuts were of the wrong configuration in that case.

Mr Adams retorted that the country had no interest in what happened to the Taoiseach's car.